I didn't know Aquamira might require a 4 hour wait to kill giardia. Need to start reading labels closer I guess. Maybe I should look into alternatives. Kind of scary to think I might not have been protecting myself against giardia for the past year while using Aquamira.

Operator Error and Chemical Water Treatment
on 08/15/2012 11:37:08 MDT

All of the chemical methods require diligence to ensure they work correctly. Even with simple Potable Aqua tablets (two step, iodine followed by neutralizer), operator error can be a concern.

On a Sierra 50 mile trek with Scouts one summer, we issued Potable Aqua with simple instructions: “Add the iodine tablet to 1 L of water, shake after 5 minutes, let sit for a total of ½ hour, then add the neutralizer.” Pretty straightforward, right? Toward the end of the trip, I observed one of the “new” dads first adding the neutralizer, waiting, then adding the dark iodine tablet. Of course, this rendered the entire exercise moot. He had been using this sequence the entire trip! Fortunately, no ill effects – we must have chosen good water sources. I always think of this when I read the “to treat or not to treat” discussions (which I don't seek to revive here).

Anyway, not correctly following directions can be equivalent to not treating!

What happened to Klearwater? I used to buy this from BPL and used it for years with great success. So much handier than the 2-part chlorine dioxide. Doesn't seem to be available from anywhere online at the moment, although the manufacturer's web site is still active. And apparently I missed it when BPL stopped selling gear anymore? That's what you get for having a child and being out of the loop for a few years I guess! ;-)

I have been using Aqua Mira for a long time and have never waited 4 hours, of course the fact I didn't get sick proves nothing. The worse case scenario used for EPA approval of chemical treatment is cold and cloudy water, the article references this. I always assumed that it was the cloudy part, lots of organic matter, that caused the 4 hour wait no so much the cold. All my hiking is in the mountains where the water runs clear. Fact is based on the test method we only know it takes 4 hours to work in cold and cloudy and we have no clue about clear and cold. I would say among the different people I know we have a combined trail time of a couple hundred days using Aquamira with no fall out that I know of. Again it doesn't prove anything but food for thought.

Micropur MP1 from Katadyn is sold in the USA and is Chlorine Dioxide and has EPA approval. Again under EPA protocol, kills everything in 30 minutes in warm clear water, 4 hours for cloudy and cold water.

Katadyn makes other products for long term water storage which is what the article references, Micropur Forte MT1 and is not the same thing.

John, you beat me to it--Katadyn Micropur has been around (with EPA approval) quite a few years longer than the Aquamira ClO2 tablets and, yes, it is chlorine dioxide.

I read reports a couple of years ago, shortly after the Aquamira tabs came out, that both brands are made in the same factory in Spain and are therefore probably identical. I have no idea whether this is true, but it seemed like an interesting factoid at the time. That is why it stuck in my memory.

While I know that the liquid Aquamira is a little cheaper, I see no reason why anyone would want to use that instead of the tablets, considering all the fuss and bother. It may be that people are misled by the treatment times on the label. As pointed out in the article, the liquid is approved only for bacteria and viruses, and the treatment time reflects that. I hope that Aquamira gets the EPA approval.

It would be wonderful if a reputable source would test the ClO2 treatment times to kill giardia and crypto cysts in CLEAR water at, say, 45*-50*F. That's the condition of most of the mountain water that I encounter! As it is, we know that the treatment time is 4 hours for the worst possible scenario, turbid water at 40*F.

Katadyn now says the treatment time for protozoan cysts in clear cold water is 2 hours, which is a help. I personally would rather carry a lightweight filter such as the Sawyer Squeeze or my homemade gravity setup using a Katadyn Hiker Pro (6 oz. including the dirty water bag), see Cola Vaughan's setup at http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=8994&startat=20 rather than carry a liter or two of extra water undergoing treatment. Of course if you're on a dry ridge with no water sources during the day, you're carrying the water anyway. Most of the places I backpack, though, have a water source at least every hour.

None of this will do you much good, of course, if you don't wash hands before handling food and after toilet functions, and resist the temptation to share gorp that may have been handled by unclean hands. There was an outbreak of Norovirus on the AT this spring, spread by unclean hands, probably not the water.

Great comments Mary. I didn't catch the 2 hour wait time for Micropur in cold water. Now I have to reasses my water treatment.

I had heard the same thing that both brands of chloring dioxide tablets are from the same company.

As I understand it McNett chose not to get EPA approval on the Aquamira liquid because EPA requires you to only list instructions for worse case scenario, cold and cloudy water, which would be the 4 hours wait time.

MSR has a chemical treatment coming out, I understand it something that has been on the market in Ireland for sometime.

I too think they are the best of the bunch as they are a stable pre-mix so no counting drops.

Unfortunately for us hikers their entire production is taken by the military now. They did not even have a booth at the OR Show that I saw this year.

I still have some that is active. It has an amazing shelf life.

I am the guy in the picture using the drops. While Roger said that the drops are added to a 1 L bottle you notice I am adding it to 2 & 3 L Hoser bottles. I just make enough mix and do the entire batch, letting those hydration bladders sit overnight, ready for the next day's hiking.

A rep from AquaMira suggested the following to avoid long waits. ClO2 quickly kills the small stuff, and then it's easy to filter out the big stuff using an AquaMira Frontier Pro inline filter. We tried it and it seemed to work pretty well.

We just used it to drink recently treated water, and didn't bother filtering water we let sit overnight. For the latter we used lower doses since the long contact time easily makes up for the lower dose (keep it out of sunlight, though, since I read that UV or something deactivates the ClO2).

I haven't hiked in areas with dodgy water for a while, but if I were to then it seems like a combo treatment would work well. Filtering followed by chemical or UV. Most of the problems with UV and chemical treatments would seem to be fixed by pre-filtering with a relatively coarse (i.e. easy to use and resistant to blocking) filter.

Filtering to remove the (relatively large) protozoa that are chemical and UV resistant will also remove a lot of the non-living material (detritus, clay particles) that will block UV and absorb (waste) the chemical treatment. The follow-up chemical or UV treatment will then be more effective against the (also now smaller) bacteria and virus load.

The question is whether there is a filter + UV combo that is still reasonably lightweight and not too expensive - the answer will of course depend on how bad the water is.

re: A Survey of Water Hazards and Water Treatment Methods - Part 4: Chemical Methods
on 08/20/2012 08:02:25 MDT

Andrew raises an interesting question concerning some combo strategies: use chemical treatment and then filter, or filter then chemical treatment. I can see advantages and disadvantages with both.

Note that some inline filters, such as the Frontier Pro, are designed to work after chemical treatment, as the filter is delivers water directly to your mouth via a bite-valve, not to another storage device. But I suppose something could be jury-rigged...

I am a little dismayed by the complete dis of chlorine (not that I use it myself, but...) Bias is clear in that section of the write-up, using such phrases as "may," "may or may not," "...in sufficient quantity," or "yuk," when it would have taken little time to look up the chemical concentrations for all of these things. A flaw in an otherwise good series of articles from an author who fancies himself scientific. You could have said "chlorine kills all of these bugs, but it takes this time multiplied by this concentration for each one, whereas the threshold for chlorine taste is this much" instead of making unsubstantiated generalizations.

Chlorine is one of the most effective and likely THE most cost effective disinfectant available for drinking water. It is used by the majority of community water systems in the US for that reason; most water systems have to jump through a few hoops (even if small ones) to get approved to use another chemical (note that chemical disinfection is required for virtually all public community water systems in the US). You can get a gallon of "NSF 61" rated sodium hypochlorite, ie acceptable for use in drinking water, in your local hot tub or spa supply store for a fraction the unit cost of the other chemicals mentioned. Regular chlorine bleach is even cheaper, available anywhere, and is chemically almost identical, with just a few potential impurities and of course it is usually more dilute. Not that you're likely to need a gallon unless you have a large group of people needing water treatment for a long time, the biggest downside to the chlorine route in my mind.

Chlorine is usually associated with bad taste. While admittedly I have never ran a water system for a community of a million people and don't know the objectives or necessities, in my opinion water that tastes like chlorine was badly managed. Chlorine is effective at lower levels than the thresholds of taste and smell. At that level you do have to wait longer, but four hours was quoted for other chemicals as well. Basically, it is just as effective and with the same limitations and drawbacks as the other chemicals mentioned, but at a fraction the cost. Realistically, only iodine on the list is similarly effective, safe, and proven.

Again, I have not yet seen a need to use chemicals in my own water, but I would say ordinary sodium hypochlorite is an effective tool for disinfection that should not be dismissed because of a pre-existing bias (or possibly because it is so cheap and generic, and thus does not play into the boutique consumer-oriented nature of much lightweight backpacking).

FYI I sent Klearwater an e-mail asking if their product was currently available to the general public from any vendor. Here's their response:

"KlearWater for civilian use will not be available again until early spring 2013. We sincerely apologize to anyone we have inconvenienced however we are implementing a permanent fix to the ongoing supply problem which we anticipate will permanently end this issue."

So keep your fingers crossed! I'm looking forward to being able to get it again.

Right, from the EPA chapter on Chlorine Dioxide:"Gregory et al. (1998) found that even under the most favorable conditions (i.e., at a pH of 8.5), required doses to achieve 2-log Cryptosporidium inactivation do not appear to be a feasible alternative, requiring doses of more than 3.0 mg/L with a 60 minute detention time. At neutral pH levels, the required doses may be more than 20 mg/L."

The EPA maximum contaminant level for Chlorine Dioxide is 0.8 mg/L, so a dose of chlorine dioxide that would inactivate crypto would also be pretty bad for you.

Compare with a maximum contaminant level of 4.0 mg/L for chlorine. While chlorine dioxide may be somewhat more effective as a biocide than chlorine, it is even easier to take a harmful dose to yourself. Which, in addition to it's higher cost, is the reason it is not commonly used in public water systems.

The point here is there is no magical chemical bullet. However, chlorine "bleach" is as good as anything when all trade offs are considered, and can be obtained at a lower price. If there was an apocalypse, zombie or otherwise, "bleach" would be my tool of choice. Note that it does turn clothes white if spilled.

I've been using Aqua Mira for more than 10 years, between 500 and 1000 trail miles a year, so drinking quite a bit of water treated with this stuff. I have yet to get sick on the trail or afterwards with anything that could be reasonably traced back to water. Of course, here in Europe as far as I can tell nobody treats there water despite the fact that cows are crapping in just about every spring there is, so maybe this is all just an unnecessary illusion...

In any case, I've noticed every now and then that when I dump my yellow treatment into the water bottle a not so pleasant gas forms. Usually it is gone before I drink the water, but it is a bit disconcerting. Anyone else experiencing this?

On a four day canyon trip in Utah I picked up a 2 month case of what I believe was giardia. I later found out that there were beavers working upstream from where we were camping. On this trip I used Aqua Mira drops and waited 20 to 30 minutes before drinking as the water was clear and cold. My buddy on the trip used a pump filter that did not take out small pathogens like bacteria but did catch protozoans. He did not get sick. I still use AM but only at higher elevations and I wait at least an hour or longer to drink. In canyon country I now filter.